The central goal of this proposal is to understand the role of activity in LMAN during song development. First, activity will be removed from LMAN by using reversible pharmacological lesion, and it is hypothesized that this will cause an increase in song stereotypy similar to permanent lesions of LMAN. To determine whether LMAN can have acute effects on song, activity will be induced in LMAN using direct electrical stimulation. This experiment will address the question whether LMAN can produce vocalizations or disrupt ongoing song during sensory motor learning. Also, LMAN will be chronically stimulated throughout sensory motor learning to observe how LMAN can affect song quality long-term. The second part of this proposal will determine the relevance of low-threshold Ca++ spike, (LTS) present in only young zebra finch LMAN neurons, to sensory acquisition. This first will be tested by recording intra-cellularly from LMAN neurons from acoustically isolated zebra finches. Isolating zebra finches serves to extend the critical period of sensory acquisition, and thus should also delay the disappearance on the LTS. Next, an antagonist of the LTS will be infused into LMAN via cannulae to determine whether blocking the LTS can decrease the amount of syllables a young zebra finch can copy from its tutor during song learning.